It's all about expectations. 

On Friday night, I wrote that "John McCain was the more effective combatant" in this year's inaugural presidential debate. A lot of commenters disagreed--some respectfully, some not so respectfully. As evidence, many cited a pair of instapolls released after the clash. CNN showed Obama winning 51 percent to 38 percent among all viewers; CBS gave him a 39-25 edge among undecideds. "As the results of the polls of THE PEOPLE showed, your conclusion that McCain won the debate... is condescending," wrote reader S.K. "You imply that the American people were too stupid to follow the logic and sophistication of Sen Obama's carefully thought out answers."

I stand by my conclusion about McCain's solid performance. My point Friday wasn't that Americans are too dumb to understand Obama's nuanced arguments. It was that by relentlessly steering the conversation to his areas of strength, McCain "did more to reinforce his message--I'm a tough leader who will cut waste and get Iraq right--than his opponent." Jay Cost over at Real Clear Politics said it best: "Obama showed up to debate. McCain showed up to say what he wanted. This meant that Obama was left debating on McCain's best topics, but McCain hardly ever debated on Obama's best topics." At first blush, I assumed this strategic advantage would help McCain "win over" more swing voters and therefore "win" the debate--despite the way he "scowled, smirked and refused to look at his rival, conveying an air of condescension that could turn off some undecideds." But after a weekend of reflection--and a harder look at some more reliable poll numbers--I think it was Obama, not McCain, who did the most to help himself in Mississippi.

The reason? Expectations--or, more specifically, the vast differences between my expectations and the expectations of a casual, low-information voter who has yet to choose between the candidates. As an associate editor and political blogger at NEWSWEEK, I've been following McCain and Obama for more than a year. I've seen each candidate speak in person on a dozen occasions. I analyze their every maneuver. But the most relevant viewers for Friday night's debate were nothing like me. They don't read blogs. They hadn't watched any of the 30 or so primary debates. And they'd probably never seen Obama or McCain speak, whether in person or on TV. For tens of millions of people, Friday was their first actual exposure to this year's crop of candidates.

My expectations for Obama were relatively realistic. I know from personal experience that he's a sensible, rational, confident member of the American political mainstream. But many casual voters, as the Atlantic's Marc Ambinder notes, probably expected to see someone a bit more radical on stage. "Think of the 'bitter' comment, his middle name, the flag pin, the Chicago connections," he notes. "Low information voters wouldn't be out of line if they had a pretty strong impression of Obama formed by these attributes." So what ended up happening, I think, is that I took the most important information conveyed on screen--that Obama is NOT a radical--for granted. I already knew that Obama would come off as smart, sober, congenial and unthreatening. But a lot of voters--many of them eminently swingable--did not. And they were duly impressed when he did. "This weird racial/ideological caricature was priced into our (campaigns, media) debate expectations," writes Ambinder. "Obama coming off as a sensible, middle of the road senator actually did him a world of good as far as the reassurance of sensibility."

The proof is in the pudding. According to a Bloomberg News/Los Angeles Times poll released Sunday, 44 percent of uncommitted viewers said Obama looked more presidential than McCain. Only 16 percent gave the Arizonan an advantage. The fact is, most voters assumed that McCain--an older, more familiar face--was "presidential" coming into the debate. He could only disappoint. Obama--or at least the mythical "Ayers-Wright Chicago Elite Radical" Obama--had a much lower bar to clear. And he cleared it with ease. This may not have surprised me, but it did surprise the people--i.e., swing voters--who actually matter.

Needless to say, this revelation doesn't bode well for McCain's campaign. It's not that McCain performed poorly on Friday. Much the opposite--it was as strong a showing as I've ever seen from him. Sure, committed Obamans will obsess over McCain's smirks, his "condescension" and his lack of eye contact, and compare him, as one particularly combative reader did, to a "100-year-old retard." But these people are irrelevant; they were voting for Obama before the debate and they're still voting for him after. Among swing voters, it's unlikely that McCain did himself any real damage. No undecided will break for Obama because McCain seemed disdainful. In fact, the Bloomberg/L.A. Times poll cited above shows that among viewers who changed their mind about whether the candidates have "the right experience to be president," the net swing toward McCain (+6 percent) was larger than the swing toward Obama (+0 percent)--which lends credence to my "more effective messaging" argument. The problem for McCain is that the debate was less about his message than Obama's image--especially among low-information swing voters. Before, McCain was hoping to convince this crucial swath of the electorate that his rival is a dangerous, radical neophyte. But Friday's face-off showed how easily they'll dismiss this caricature once they actually see Obama speak. On issue after issue, McCain said Obama "didn't understand." But on issue after issue, Obama sounded credibly presidential. If that's the dominant dynamic from now until November, McCain's going to have a tough time coming from behind on Election Day--no matter how many debates he "wins" among hacks like me.